Fuel systems for most modern automotive engines utilize fuel injectors to deliver liquid fuel to the engine cylinders for combustion. The fuel injectors are mounted on a fuel rail to which liquid fuel is supplied from a liquid fuel tank by a pump. A pressure regulator maintains the required injector operational pressure. Excess liquid fuel that is not injected to the cylinders may be returned to the fuel tank by a fuel return line.
The generation of vapor in the liquid fuel tank may require a secondary system, i.e an evaporative emission control system, for controlling vapor emissions from the liquid fuel in the fuel tank. The evaporative emission control system includes a fuel vapor collection canister, e.g. a carbon or charcoal canister, that is connected to the headspace of the fuel tank to absorb and retain fuel vapor. The evaporative emission control system further includes a canister purge valve between the fuel tank and an intake manifold of the engine. An engine control management computer supplies a control signal for operating the canister purge valve to allow vapor flow from the tank headspace and the vapor collection canister to the engine intake manifold, where the vapor is consumed in the combustion process.
It is believed that there is a need for a fuel system that controls vapor emissions, and that generates and supplies vapor fuel, to an evaporative fuel vapor engine, thus modifying or eliminating the need for liquid fuel delivery to the engine cylinders.